drivers/dma/stm32-dma.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for STM32 DMA controller
   4  *
   5  * Inspired by dma-jz4740.c and tegra20-apb-dma.c
   6  *
   7  * Copyright (C) M'boumba Cedric Madianga 2015
   8  * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
   9  *         Pierre-Yves Mordret <pierre-yves.mordret@st.com>
  10  */
  11
  12 #include <linux/bitfield.h>
  13 #include <linux/clk.h>
  14 #include <linux/delay.h>
  15 #include <linux/dmaengine.h>
  16 #include <linux/dma-mapping.h>
  17 #include <linux/err.h>
  18 #include <linux/init.h>
  19 #include <linux/iopoll.h>
  20 #include <linux/jiffies.h>
  21 #include <linux/list.h>
  22 #include <linux/module.h>
  23 #include <linux/of.h>
  24 #include <linux/of_device.h>
  25 #include <linux/of_dma.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/pm_runtime.h>
  28 #include <linux/reset.h>
  29 #include <linux/sched.h>
  30 #include <linux/slab.h>
  31
  32 #include "virt-dma.h"
  33
  34 #define STM32_DMA_LISR                  0x0000 /* DMA Low Int Status Reg */
  35 #define STM32_DMA_HISR                  0x0004 /* DMA High Int Status Reg */
  36 #define STM32_DMA_ISR(n)                (((n) & 4) ? STM32_DMA_HISR : STM32_DMA_LISR)
  37 #define STM32_DMA_LIFCR                 0x0008 /* DMA Low Int Flag Clear Reg */
  38 #define STM32_DMA_HIFCR                 0x000c /* DMA High Int Flag Clear Reg */
  39 #define STM32_DMA_IFCR(n)               (((n) & 4) ? STM32_DMA_HIFCR : STM32_DMA_LIFCR)
  40 #define STM32_DMA_TCI                   BIT(5) /* Transfer Complete Interrupt */
  41 #define STM32_DMA_HTI                   BIT(4) /* Half Transfer Interrupt */
  42 #define STM32_DMA_TEI                   BIT(3) /* Transfer Error Interrupt */
  43 #define STM32_DMA_DMEI                  BIT(2) /* Direct Mode Error Interrupt */
  44 #define STM32_DMA_FEI                   BIT(0) /* FIFO Error Interrupt */
  45 #define STM32_DMA_MASKI                 (STM32_DMA_TCI \
  46                                          | STM32_DMA_TEI \
  47                                          | STM32_DMA_DMEI \
  48                                          | STM32_DMA_FEI)
  49 /*
  50  * If (chan->id % 4) is 2 or 3, left shift the mask by 16 bits;
  51  * if (ch % 4) is 1 or 3, additionally left shift the mask by 6 bits.
  52  */
  53 #define STM32_DMA_FLAGS_SHIFT(n)        ({ typeof(n) (_n) = (n); \
  54                                            (((_n) & 2) << 3) | (((_n) & 1) * 6); })
  55
  56 /* DMA Stream x Configuration Register */
  57 #define STM32_DMA_SCR(x)                (0x0010 + 0x18 * (x)) /* x = 0..7 */
  58 #define STM32_DMA_SCR_REQ_MASK          GENMASK(27, 25)
  59 #define STM32_DMA_SCR_MBURST_MASK       GENMASK(24, 23)
  60 #define STM32_DMA_SCR_PBURST_MASK       GENMASK(22, 21)
  61 #define STM32_DMA_SCR_PL_MASK           GENMASK(17, 16)
  62 #define STM32_DMA_SCR_MSIZE_MASK        GENMASK(14, 13)
  63 #define STM32_DMA_SCR_PSIZE_MASK        GENMASK(12, 11)
  64 #define STM32_DMA_SCR_DIR_MASK          GENMASK(7, 6)
  65 #define STM32_DMA_SCR_TRBUFF            BIT(20) /* Bufferable transfer for USART/UART */
  66 #define STM32_DMA_SCR_CT                BIT(19) /* Target in double buffer */
  67 #define STM32_DMA_SCR_DBM               BIT(18) /* Double Buffer Mode */
  68 #define STM32_DMA_SCR_PINCOS            BIT(15) /* Peripheral inc offset size */
  69 #define STM32_DMA_SCR_MINC              BIT(10) /* Memory increment mode */
  70 #define STM32_DMA_SCR_PINC              BIT(9) /* Peripheral increment mode */
  71 #define STM32_DMA_SCR_CIRC              BIT(8) /* Circular mode */
  72 #define STM32_DMA_SCR_PFCTRL            BIT(5) /* Peripheral Flow Controller */
  73 #define STM32_DMA_SCR_TCIE              BIT(4) /* Transfer Complete Int Enable
  74                                                 */
  75 #define STM32_DMA_SCR_TEIE              BIT(2) /* Transfer Error Int Enable */
  76 #define STM32_DMA_SCR_DMEIE             BIT(1) /* Direct Mode Err Int Enable */
  77 #define STM32_DMA_SCR_EN                BIT(0) /* Stream Enable */
  78 #define STM32_DMA_SCR_CFG_MASK          (STM32_DMA_SCR_PINC \
  79                                         | STM32_DMA_SCR_MINC \
  80                                         | STM32_DMA_SCR_PINCOS \
  81                                         | STM32_DMA_SCR_PL_MASK)
  82 #define STM32_DMA_SCR_IRQ_MASK          (STM32_DMA_SCR_TCIE \
  83                                         | STM32_DMA_SCR_TEIE \
  84                                         | STM32_DMA_SCR_DMEIE)
  85
  86 /* DMA Stream x number of data register */
  87 #define STM32_DMA_SNDTR(x)              (0x0014 + 0x18 * (x))
  88
  89 /* DMA stream peripheral address register */
  90 #define STM32_DMA_SPAR(x)               (0x0018 + 0x18 * (x))
  91
  92 /* DMA stream x memory 0 address register */
  93 #define STM32_DMA_SM0AR(x)              (0x001c + 0x18 * (x))
  94
  95 /* DMA stream x memory 1 address register */
  96 #define STM32_DMA_SM1AR(x)              (0x0020 + 0x18 * (x))
  97
  98 /* DMA stream x FIFO control register */
  99 #define STM32_DMA_SFCR(x)               (0x0024 + 0x18 * (x))
 100 #define STM32_DMA_SFCR_FTH_MASK         GENMASK(1, 0)
 101 #define STM32_DMA_SFCR_FEIE             BIT(7) /* FIFO error interrupt enable */
 102 #define STM32_DMA_SFCR_DMDIS            BIT(2) /* Direct mode disable */
 103 #define STM32_DMA_SFCR_MASK             (STM32_DMA_SFCR_FEIE \
 104                                         | STM32_DMA_SFCR_DMDIS)
 105
 106 /* DMA direction */
 107 #define STM32_DMA_DEV_TO_MEM            0x00
 108 #define STM32_DMA_MEM_TO_DEV            0x01
 109 #define STM32_DMA_MEM_TO_MEM            0x02
 110
 111 /* DMA priority level */
 112 #define STM32_DMA_PRIORITY_LOW          0x00
 113 #define STM32_DMA_PRIORITY_MEDIUM       0x01
 114 #define STM32_DMA_PRIORITY_HIGH         0x02
 115 #define STM32_DMA_PRIORITY_VERY_HIGH    0x03
 116
 117 /* DMA FIFO threshold selection */
 118 #define STM32_DMA_FIFO_THRESHOLD_1QUARTERFULL           0x00
 119 #define STM32_DMA_FIFO_THRESHOLD_HALFFULL               0x01
 120 #define STM32_DMA_FIFO_THRESHOLD_3QUARTERSFULL          0x02
 121 #define STM32_DMA_FIFO_THRESHOLD_FULL                   0x03
 122 #define STM32_DMA_FIFO_THRESHOLD_NONE                   0x04
 123
 124 #define STM32_DMA_MAX_DATA_ITEMS        0xffff
 125 /*
 126  * Valid transfer starts from @0 to @0xFFFE leading to unaligned scatter
 127  * gather at boundary. Thus it's safer to round down this value on FIFO
 128  * size (16 Bytes)
 129  */
 130 #define STM32_DMA_ALIGNED_MAX_DATA_ITEMS        \
 131         ALIGN_DOWN(STM32_DMA_MAX_DATA_ITEMS, 16)
 132 #define STM32_DMA_MAX_CHANNELS          0x08
 133 #define STM32_DMA_MAX_REQUEST_ID        0x08
 134 #define STM32_DMA_MAX_DATA_PARAM        0x03
 135 #define STM32_DMA_FIFO_SIZE             16      /* FIFO is 16 bytes */
 136 #define STM32_DMA_MIN_BURST             4
 137 #define STM32_DMA_MAX_BURST             16
 138
 139 /* DMA Features */
 140 #define STM32_DMA_THRESHOLD_FTR_MASK    GENMASK(1, 0)
 141 #define STM32_DMA_DIRECT_MODE_MASK      BIT(2)
 142 #define STM32_DMA_ALT_ACK_MODE_MASK     BIT(4)
 143 #define STM32_DMA_MDMA_STREAM_ID_MASK   GENMASK(19, 16)
 144
 145 enum stm32_dma_width {
 146         STM32_DMA_BYTE,
 147         STM32_DMA_HALF_WORD,
 148         STM32_DMA_WORD,
 149 };
 150
 151 enum stm32_dma_burst_size {
 152         STM32_DMA_BURST_SINGLE,
 153         STM32_DMA_BURST_INCR4,
 154         STM32_DMA_BURST_INCR8,
 155         STM32_DMA_BURST_INCR16,
 156 };
 157
 158 /**
 159  * struct stm32_dma_cfg - STM32 DMA custom configuration
 160  * @channel_id: channel ID
 161  * @request_line: DMA request
 162  * @stream_config: 32bit mask specifying the DMA channel configuration
 163  * @features: 32bit mask specifying the DMA Feature list
 164  */
 165 struct stm32_dma_cfg {
 166         u32 channel_id;
 167         u32 request_line;
 168         u32 stream_config;
 169         u32 features;
 170 };
 171
 172 struct stm32_dma_chan_reg {
 173         u32 dma_lisr;
 174         u32 dma_hisr;
 175         u32 dma_lifcr;
 176         u32 dma_hifcr;
 177         u32 dma_scr;
 178         u32 dma_sndtr;
 179         u32 dma_spar;
 180         u32 dma_sm0ar;
 181         u32 dma_sm1ar;
 182         u32 dma_sfcr;
 183 };
 184
 185 struct stm32_dma_sg_req {
 186         u32 len;
 187         struct stm32_dma_chan_reg chan_reg;
 188 };
 189
 190 struct stm32_dma_desc {
 191         struct virt_dma_desc vdesc;
 192         bool cyclic;
 193         u32 num_sgs;
 194         struct stm32_dma_sg_req sg_req[];
 195 };
 196
 197 /**
 198  * struct stm32_dma_mdma_config - STM32 DMA MDMA configuration
 199  * @stream_id: DMA request to trigger STM32 MDMA transfer
 200  * @ifcr: DMA interrupt flag clear register address,
 201  *        used by STM32 MDMA to clear DMA Transfer Complete flag
 202  * @tcf: DMA Transfer Complete flag
 203  */
 204 struct stm32_dma_mdma_config {
 205         u32 stream_id;
 206         u32 ifcr;
 207         u32 tcf;
 208 };
 209
 210 struct stm32_dma_chan {
 211         struct virt_dma_chan vchan;
 212         bool config_init;
 213         bool busy;
 214         u32 id;
 215         u32 irq;
 216         struct stm32_dma_desc *desc;
 217         u32 next_sg;
 218         struct dma_slave_config dma_sconfig;
 219         struct stm32_dma_chan_reg chan_reg;
 220         u32 threshold;
 221         u32 mem_burst;
 222         u32 mem_width;
 223         enum dma_status status;
 224         bool trig_mdma;
 225         struct stm32_dma_mdma_config mdma_config;
 226 };
 227
 228 struct stm32_dma_device {
 229         struct dma_device ddev;
 230         void __iomem *base;
 231         struct clk *clk;
 232         bool mem2mem;
 233         struct stm32_dma_chan chan[STM32_DMA_MAX_CHANNELS];
 234 };
 235
 236 static struct stm32_dma_device *stm32_dma_get_dev(struct stm32_dma_chan *chan)
 237 {
 238         return container_of(chan->vchan.chan.device, struct stm32_dma_device,
 239                             ddev);
 240 }
 241
 242 static struct stm32_dma_chan *to_stm32_dma_chan(struct dma_chan *c)
 243 {
 244         return container_of(c, struct stm32_dma_chan, vchan.chan);
 245 }
 246
 247 static struct stm32_dma_desc *to_stm32_dma_desc(struct virt_dma_desc *vdesc)
 248 {
 249         return container_of(vdesc, struct stm32_dma_desc, vdesc);
 250 }
 251
 252 static struct device *chan2dev(struct stm32_dma_chan *chan)
 253 {
 254         return &chan->vchan.chan.dev->device;
 255 }
 256
 257 static u32 stm32_dma_read(struct stm32_dma_device *dmadev, u32 reg)
 258 {
 259         return readl_relaxed(dmadev->base + reg);
 260 }
 261
 262 static void stm32_dma_write(struct stm32_dma_device *dmadev, u32 reg, u32 val)
 263 {
 264         writel_relaxed(val, dmadev->base + reg);
 265 }
 266
 267 static int stm32_dma_get_width(struct stm32_dma_chan *chan,
 268                                enum dma_slave_buswidth width)
 269 {
 270         switch (width) {
 271         case DMA_SLAVE_BUSWIDTH_1_BYTE:
 272                 return STM32_DMA_BYTE;
 273         case DMA_SLAVE_BUSWIDTH_2_BYTES:
 274                 return STM32_DMA_HALF_WORD;
 275         case DMA_SLAVE_BUSWIDTH_4_BYTES:
 276                 return STM32_DMA_WORD;
 277         default:
 278                 dev_err(chan2dev(chan), "Dma bus width not supported\n");
 279                 return -EINVAL;
 280         }
 281 }
 282
 283 static enum dma_slave_buswidth stm32_dma_get_max_width(u32 buf_len,
 284                                                        dma_addr_t buf_addr,
 285                                                        u32 threshold)
 286 {
 287         enum dma_slave_buswidth max_width;
 288
 289         if (threshold == STM32_DMA_FIFO_THRESHOLD_FULL)
 290                 max_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 291         else
 292                 max_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 293
 294         while ((buf_len < max_width  || buf_len % max_width) &&
 295                max_width > DMA_SLAVE_BUSWIDTH_1_BYTE)
 296                 max_width = max_width >> 1;
 297
 298         if (buf_addr & (max_width - 1))
 299                 max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 300
 301         return max_width;
 302 }
 303
 304 static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold,
 305                                                 enum dma_slave_buswidth width)
 306 {
 307         u32 remaining;
 308
 309         if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE)
 310                 return false;
 311
 312         if (width != DMA_SLAVE_BUSWIDTH_UNDEFINED) {
 313                 if (burst != 0) {
 314                         /*
 315                          * If number of beats fit in several whole bursts
 316                          * this configuration is allowed.
 317                          */
 318                         remaining = ((STM32_DMA_FIFO_SIZE / width) *
 319                                      (threshold + 1) / 4) % burst;
 320
 321                         if (remaining == 0)
 322                                 return true;
 323                 } else {
 324                         return true;
 325                 }
 326         }
 327
 328         return false;
 329 }
 330
 331 static bool stm32_dma_is_burst_possible(u32 buf_len, u32 threshold)
 332 {
 333         /* If FIFO direct mode, burst is not possible */
 334         if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE)
 335                 return false;
 336
 337         /*
 338          * Buffer or period length has to be aligned on FIFO depth.
 339          * Otherwise bytes may be stuck within FIFO at buffer or period
 340          * length.
 341          */
 342         return ((buf_len % ((threshold + 1) * 4)) == 0);
 343 }
 344
 345 static u32 stm32_dma_get_best_burst(u32 buf_len, u32 max_burst, u32 threshold,
 346                                     enum dma_slave_buswidth width)
 347 {
 348         u32 best_burst = max_burst;
 349
 350         if (best_burst == 1 || !stm32_dma_is_burst_possible(buf_len, threshold))
 351                 return 0;
 352
 353         while ((buf_len < best_burst * width && best_burst > 1) ||
 354                !stm32_dma_fifo_threshold_is_allowed(best_burst, threshold,
 355                                                     width)) {
 356                 if (best_burst > STM32_DMA_MIN_BURST)
 357                         best_burst = best_burst >> 1;
 358                 else
 359                         best_burst = 0;
 360         }
 361
 362         return best_burst;
 363 }
 364
 365 static int stm32_dma_get_burst(struct stm32_dma_chan *chan, u32 maxburst)
 366 {
 367         switch (maxburst) {
 368         case 0:
 369         case 1:
 370                 return STM32_DMA_BURST_SINGLE;
 371         case 4:
 372                 return STM32_DMA_BURST_INCR4;
 373         case 8:
 374                 return STM32_DMA_BURST_INCR8;
 375         case 16:
 376                 return STM32_DMA_BURST_INCR16;
 377         default:
 378                 dev_err(chan2dev(chan), "Dma burst size not supported\n");
 379                 return -EINVAL;
 380         }
 381 }
 382
 383 static void stm32_dma_set_fifo_config(struct stm32_dma_chan *chan,
 384                                       u32 src_burst, u32 dst_burst)
 385 {
 386         chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_MASK;
 387         chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_DMEIE;
 388
 389         if (!src_burst && !dst_burst) {
 390                 /* Using direct mode */
 391                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_DMEIE;
 392         } else {
 393                 /* Using FIFO mode */
 394                 chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
 395         }
 396 }
 397
 398 static int stm32_dma_slave_config(struct dma_chan *c,
 399                                   struct dma_slave_config *config)
 400 {
 401         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 402
 403         memcpy(&chan->dma_sconfig, config, sizeof(*config));
 404
 405         /* Check if user is requesting DMA to trigger STM32 MDMA */
 406         if (config->peripheral_size) {
 407                 config->peripheral_config = &chan->mdma_config;
 408                 config->peripheral_size = sizeof(chan->mdma_config);
 409                 chan->trig_mdma = true;
 410         }
 411
 412         chan->config_init = true;
 413
 414         return 0;
 415 }
 416
 417 static u32 stm32_dma_irq_status(struct stm32_dma_chan *chan)
 418 {
 419         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 420         u32 flags, dma_isr;
 421
 422         /*
 423          * Read "flags" from DMA_xISR register corresponding to the selected
 424          * DMA channel at the correct bit offset inside that register.
 425          */
 426
 427         dma_isr = stm32_dma_read(dmadev, STM32_DMA_ISR(chan->id));
 428         flags = dma_isr >> STM32_DMA_FLAGS_SHIFT(chan->id);
 429
 430         return flags & STM32_DMA_MASKI;
 431 }
 432
 433 static void stm32_dma_irq_clear(struct stm32_dma_chan *chan, u32 flags)
 434 {
 435         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 436         u32 dma_ifcr;
 437
 438         /*
 439          * Write "flags" to the DMA_xIFCR register corresponding to the selected
 440          * DMA channel at the correct bit offset inside that register.
 441          */
 442         flags &= STM32_DMA_MASKI;
 443         dma_ifcr = flags << STM32_DMA_FLAGS_SHIFT(chan->id);
 444
 445         stm32_dma_write(dmadev, STM32_DMA_IFCR(chan->id), dma_ifcr);
 446 }
 447
 448 static int stm32_dma_disable_chan(struct stm32_dma_chan *chan)
 449 {
 450         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 451         u32 dma_scr, id, reg;
 452
 453         id = chan->id;
 454         reg = STM32_DMA_SCR(id);
 455         dma_scr = stm32_dma_read(dmadev, reg);
 456
 457         if (dma_scr & STM32_DMA_SCR_EN) {
 458                 dma_scr &= ~STM32_DMA_SCR_EN;
 459                 stm32_dma_write(dmadev, reg, dma_scr);
 460
 461                 return readl_relaxed_poll_timeout_atomic(dmadev->base + reg,
 462                                         dma_scr, !(dma_scr & STM32_DMA_SCR_EN),
 463                                         10, 1000000);
 464         }
 465
 466         return 0;
 467 }
 468
 469 static void stm32_dma_stop(struct stm32_dma_chan *chan)
 470 {
 471         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 472         u32 dma_scr, dma_sfcr, status;
 473         int ret;
 474
 475         /* Disable interrupts */
 476         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 477         dma_scr &= ~STM32_DMA_SCR_IRQ_MASK;
 478         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
 479         dma_sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 480         dma_sfcr &= ~STM32_DMA_SFCR_FEIE;
 481         stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), dma_sfcr);
 482
 483         /* Disable DMA */
 484         ret = stm32_dma_disable_chan(chan);
 485         if (ret < 0)
 486                 return;
 487
 488         /* Clear interrupt status if it is there */
 489         status = stm32_dma_irq_status(chan);
 490         if (status) {
 491                 dev_dbg(chan2dev(chan), "%s(): clearing interrupt: 0x%08x\n",
 492                         __func__, status);
 493                 stm32_dma_irq_clear(chan, status);
 494         }
 495
 496         chan->busy = false;
 497         chan->status = DMA_COMPLETE;
 498 }
 499
 500 static int stm32_dma_terminate_all(struct dma_chan *c)
 501 {
 502         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 503         unsigned long flags;
 504         LIST_HEAD(head);
 505
 506         spin_lock_irqsave(&chan->vchan.lock, flags);
 507
 508         if (chan->desc) {
 509                 dma_cookie_complete(&chan->desc->vdesc.tx);
 510                 vchan_terminate_vdesc(&chan->desc->vdesc);
 511                 if (chan->busy)
 512                         stm32_dma_stop(chan);
 513                 chan->desc = NULL;
 514         }
 515
 516         vchan_get_all_descriptors(&chan->vchan, &head);
 517         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 518         vchan_dma_desc_free_list(&chan->vchan, &head);
 519
 520         return 0;
 521 }
 522
 523 static void stm32_dma_synchronize(struct dma_chan *c)
 524 {
 525         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 526
 527         vchan_synchronize(&chan->vchan);
 528 }
 529
 530 static void stm32_dma_dump_reg(struct stm32_dma_chan *chan)
 531 {
 532         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 533         u32 scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 534         u32 ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
 535         u32 spar = stm32_dma_read(dmadev, STM32_DMA_SPAR(chan->id));
 536         u32 sm0ar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(chan->id));
 537         u32 sm1ar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(chan->id));
 538         u32 sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 539
 540         dev_dbg(chan2dev(chan), "SCR:   0x%08x\n", scr);
 541         dev_dbg(chan2dev(chan), "NDTR:  0x%08x\n", ndtr);
 542         dev_dbg(chan2dev(chan), "SPAR:  0x%08x\n", spar);
 543         dev_dbg(chan2dev(chan), "SM0AR: 0x%08x\n", sm0ar);
 544         dev_dbg(chan2dev(chan), "SM1AR: 0x%08x\n", sm1ar);
 545         dev_dbg(chan2dev(chan), "SFCR:  0x%08x\n", sfcr);
 546 }
 547
 548 static void stm32_dma_sg_inc(struct stm32_dma_chan *chan)
 549 {
 550         chan->next_sg++;
 551         if (chan->desc->cyclic && (chan->next_sg == chan->desc->num_sgs))
 552                 chan->next_sg = 0;
 553 }
 554
 555 static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan);
 556
 557 static void stm32_dma_start_transfer(struct stm32_dma_chan *chan)
 558 {
 559         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 560         struct virt_dma_desc *vdesc;
 561         struct stm32_dma_sg_req *sg_req;
 562         struct stm32_dma_chan_reg *reg;
 563         u32 status;
 564         int ret;
 565
 566         ret = stm32_dma_disable_chan(chan);
 567         if (ret < 0)
 568                 return;
 569
 570         if (!chan->desc) {
 571                 vdesc = vchan_next_desc(&chan->vchan);
 572                 if (!vdesc)
 573                         return;
 574
 575                 list_del(&vdesc->node);
 576
 577                 chan->desc = to_stm32_dma_desc(vdesc);
 578                 chan->next_sg = 0;
 579         }
 580
 581         if (chan->next_sg == chan->desc->num_sgs)
 582                 chan->next_sg = 0;
 583
 584         sg_req = &chan->desc->sg_req[chan->next_sg];
 585         reg = &sg_req->chan_reg;
 586
 587         /* When DMA triggers STM32 MDMA, DMA Transfer Complete is managed by STM32 MDMA */
 588         if (chan->trig_mdma && chan->dma_sconfig.direction != DMA_MEM_TO_DEV)
 589                 reg->dma_scr &= ~STM32_DMA_SCR_TCIE;
 590
 591         reg->dma_scr &= ~STM32_DMA_SCR_EN;
 592         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
 593         stm32_dma_write(dmadev, STM32_DMA_SPAR(chan->id), reg->dma_spar);
 594         stm32_dma_write(dmadev, STM32_DMA_SM0AR(chan->id), reg->dma_sm0ar);
 595         stm32_dma_write(dmadev, STM32_DMA_SFCR(chan->id), reg->dma_sfcr);
 596         stm32_dma_write(dmadev, STM32_DMA_SM1AR(chan->id), reg->dma_sm1ar);
 597         stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), reg->dma_sndtr);
 598
 599         stm32_dma_sg_inc(chan);
 600
 601         /* Clear interrupt status if it is there */
 602         status = stm32_dma_irq_status(chan);
 603         if (status)
 604                 stm32_dma_irq_clear(chan, status);
 605
 606         if (chan->desc->cyclic)
 607                 stm32_dma_configure_next_sg(chan);
 608
 609         stm32_dma_dump_reg(chan);
 610
 611         /* Start DMA */
 612         chan->busy = true;
 613         chan->status = DMA_IN_PROGRESS;
 614         reg->dma_scr |= STM32_DMA_SCR_EN;
 615         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), reg->dma_scr);
 616
 617         dev_dbg(chan2dev(chan), "vchan %pK: started\n", &chan->vchan);
 618 }
 619
 620 static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan)
 621 {
 622         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 623         struct stm32_dma_sg_req *sg_req;
 624         u32 dma_scr, dma_sm0ar, dma_sm1ar, id;
 625
 626         id = chan->id;
 627         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 628
 629         sg_req = &chan->desc->sg_req[chan->next_sg];
 630
 631         if (dma_scr & STM32_DMA_SCR_CT) {
 632                 dma_sm0ar = sg_req->chan_reg.dma_sm0ar;
 633                 stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), dma_sm0ar);
 634                 dev_dbg(chan2dev(chan), "CT=1 <=> SM0AR: 0x%08x\n",
 635                         stm32_dma_read(dmadev, STM32_DMA_SM0AR(id)));
 636         } else {
 637                 dma_sm1ar = sg_req->chan_reg.dma_sm1ar;
 638                 stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), dma_sm1ar);
 639                 dev_dbg(chan2dev(chan), "CT=0 <=> SM1AR: 0x%08x\n",
 640                         stm32_dma_read(dmadev, STM32_DMA_SM1AR(id)));
 641         }
 642 }
 643
 644 static void stm32_dma_handle_chan_paused(struct stm32_dma_chan *chan)
 645 {
 646         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 647         u32 dma_scr;
 648
 649         /*
 650          * Read and store current remaining data items and peripheral/memory addresses to be
 651          * updated on resume
 652          */
 653         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 654         /*
 655          * Transfer can be paused while between a previous resume and reconfiguration on transfer
 656          * complete. If transfer is cyclic and CIRC and DBM have been deactivated for resume, need
 657          * to set it here in SCR backup to ensure a good reconfiguration on transfer complete.
 658          */
 659         if (chan->desc && chan->desc->cyclic) {
 660                 if (chan->desc->num_sgs == 1)
 661                         dma_scr |= STM32_DMA_SCR_CIRC;
 662                 else
 663                         dma_scr |= STM32_DMA_SCR_DBM;
 664         }
 665         chan->chan_reg.dma_scr = dma_scr;
 666
 667         /*
 668          * Need to temporarily deactivate CIRC/DBM until next Transfer Complete interrupt, otherwise
 669          * on resume NDTR autoreload value will be wrong (lower than the initial period length)
 670          */
 671         if (chan->desc && chan->desc->cyclic) {
 672                 dma_scr &= ~(STM32_DMA_SCR_DBM | STM32_DMA_SCR_CIRC);
 673                 stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
 674         }
 675
 676         chan->chan_reg.dma_sndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
 677
 678         chan->status = DMA_PAUSED;
 679
 680         dev_dbg(chan2dev(chan), "vchan %pK: paused\n", &chan->vchan);
 681 }
 682
 683 static void stm32_dma_post_resume_reconfigure(struct stm32_dma_chan *chan)
 684 {
 685         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 686         struct stm32_dma_sg_req *sg_req;
 687         u32 dma_scr, status, id;
 688
 689         id = chan->id;
 690         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 691
 692         /* Clear interrupt status if it is there */
 693         status = stm32_dma_irq_status(chan);
 694         if (status)
 695                 stm32_dma_irq_clear(chan, status);
 696
 697         if (!chan->next_sg)
 698                 sg_req = &chan->desc->sg_req[chan->desc->num_sgs - 1];
 699         else
 700                 sg_req = &chan->desc->sg_req[chan->next_sg - 1];
 701
 702         /* Reconfigure NDTR with the initial value */
 703         stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), sg_req->chan_reg.dma_sndtr);
 704
 705         /* Restore SPAR */
 706         stm32_dma_write(dmadev, STM32_DMA_SPAR(id), sg_req->chan_reg.dma_spar);
 707
 708         /* Restore SM0AR/SM1AR whatever DBM/CT as they may have been modified */
 709         stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), sg_req->chan_reg.dma_sm0ar);
 710         stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), sg_req->chan_reg.dma_sm1ar);
 711
 712         /* Reactivate CIRC/DBM if needed */
 713         if (chan->chan_reg.dma_scr & STM32_DMA_SCR_DBM) {
 714                 dma_scr |= STM32_DMA_SCR_DBM;
 715                 /* Restore CT */
 716                 if (chan->chan_reg.dma_scr & STM32_DMA_SCR_CT)
 717                         dma_scr &= ~STM32_DMA_SCR_CT;
 718                 else
 719                         dma_scr |= STM32_DMA_SCR_CT;
 720         } else if (chan->chan_reg.dma_scr & STM32_DMA_SCR_CIRC) {
 721                 dma_scr |= STM32_DMA_SCR_CIRC;
 722         }
 723         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
 724
 725         stm32_dma_configure_next_sg(chan);
 726
 727         stm32_dma_dump_reg(chan);
 728
 729         dma_scr |= STM32_DMA_SCR_EN;
 730         stm32_dma_write(dmadev, STM32_DMA_SCR(chan->id), dma_scr);
 731
 732         dev_dbg(chan2dev(chan), "vchan %pK: reconfigured after pause/resume\n", &chan->vchan);
 733 }
 734
 735 static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan, u32 scr)
 736 {
 737         if (!chan->desc)
 738                 return;
 739
 740         if (chan->desc->cyclic) {
 741                 vchan_cyclic_callback(&chan->desc->vdesc);
 742                 if (chan->trig_mdma)
 743                         return;
 744                 stm32_dma_sg_inc(chan);
 745                 /* cyclic while CIRC/DBM disable => post resume reconfiguration needed */
 746                 if (!(scr & (STM32_DMA_SCR_CIRC | STM32_DMA_SCR_DBM)))
 747                         stm32_dma_post_resume_reconfigure(chan);
 748                 else if (scr & STM32_DMA_SCR_DBM)
 749                         stm32_dma_configure_next_sg(chan);
 750         } else {
 751                 chan->busy = false;
 752                 chan->status = DMA_COMPLETE;
 753                 if (chan->next_sg == chan->desc->num_sgs) {
 754                         vchan_cookie_complete(&chan->desc->vdesc);
 755                         chan->desc = NULL;
 756                 }
 757                 stm32_dma_start_transfer(chan);
 758         }
 759 }
 760
 761 static irqreturn_t stm32_dma_chan_irq(int irq, void *devid)
 762 {
 763         struct stm32_dma_chan *chan = devid;
 764         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 765         u32 status, scr, sfcr;
 766
 767         spin_lock(&chan->vchan.lock);
 768
 769         status = stm32_dma_irq_status(chan);
 770         scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
 771         sfcr = stm32_dma_read(dmadev, STM32_DMA_SFCR(chan->id));
 772
 773         if (status & STM32_DMA_FEI) {
 774                 stm32_dma_irq_clear(chan, STM32_DMA_FEI);
 775                 status &= ~STM32_DMA_FEI;
 776                 if (sfcr & STM32_DMA_SFCR_FEIE) {
 777                         if (!(scr & STM32_DMA_SCR_EN) &&
 778                             !(status & STM32_DMA_TCI))
 779                                 dev_err(chan2dev(chan), "FIFO Error\n");
 780                         else
 781                                 dev_dbg(chan2dev(chan), "FIFO over/underrun\n");
 782                 }
 783         }
 784         if (status & STM32_DMA_DMEI) {
 785                 stm32_dma_irq_clear(chan, STM32_DMA_DMEI);
 786                 status &= ~STM32_DMA_DMEI;
 787                 if (sfcr & STM32_DMA_SCR_DMEIE)
 788                         dev_dbg(chan2dev(chan), "Direct mode overrun\n");
 789         }
 790
 791         if (status & STM32_DMA_TCI) {
 792                 stm32_dma_irq_clear(chan, STM32_DMA_TCI);
 793                 if (scr & STM32_DMA_SCR_TCIE) {
 794                         if (chan->status != DMA_PAUSED)
 795                                 stm32_dma_handle_chan_done(chan, scr);
 796                 }
 797                 status &= ~STM32_DMA_TCI;
 798         }
 799
 800         if (status & STM32_DMA_HTI) {
 801                 stm32_dma_irq_clear(chan, STM32_DMA_HTI);
 802                 status &= ~STM32_DMA_HTI;
 803         }
 804
 805         if (status) {
 806                 stm32_dma_irq_clear(chan, status);
 807                 dev_err(chan2dev(chan), "DMA error: status=0x%08x\n", status);
 808                 if (!(scr & STM32_DMA_SCR_EN))
 809                         dev_err(chan2dev(chan), "chan disabled by HW\n");
 810         }
 811
 812         spin_unlock(&chan->vchan.lock);
 813
 814         return IRQ_HANDLED;
 815 }
 816
 817 static void stm32_dma_issue_pending(struct dma_chan *c)
 818 {
 819         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 820         unsigned long flags;
 821
 822         spin_lock_irqsave(&chan->vchan.lock, flags);
 823         if (vchan_issue_pending(&chan->vchan) && !chan->desc && !chan->busy) {
 824                 dev_dbg(chan2dev(chan), "vchan %pK: issued\n", &chan->vchan);
 825                 stm32_dma_start_transfer(chan);
 826
 827         }
 828         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 829 }
 830
 831 static int stm32_dma_pause(struct dma_chan *c)
 832 {
 833         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 834         unsigned long flags;
 835         int ret;
 836
 837         if (chan->status != DMA_IN_PROGRESS)
 838                 return -EPERM;
 839
 840         spin_lock_irqsave(&chan->vchan.lock, flags);
 841
 842         ret = stm32_dma_disable_chan(chan);
 843         if (!ret)
 844                 stm32_dma_handle_chan_paused(chan);
 845
 846         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 847
 848         return ret;
 849 }
 850
 851 static int stm32_dma_resume(struct dma_chan *c)
 852 {
 853         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
 854         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
 855         struct stm32_dma_chan_reg chan_reg = chan->chan_reg;
 856         u32 id = chan->id, scr, ndtr, offset, spar, sm0ar, sm1ar;
 857         struct stm32_dma_sg_req *sg_req;
 858         unsigned long flags;
 859
 860         if (chan->status != DMA_PAUSED)
 861                 return -EPERM;
 862
 863         scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
 864         if (WARN_ON(scr & STM32_DMA_SCR_EN))
 865                 return -EPERM;
 866
 867         spin_lock_irqsave(&chan->vchan.lock, flags);
 868
 869         /* sg_reg[prev_sg] contains original ndtr, sm0ar and sm1ar before pausing the transfer */
 870         if (!chan->next_sg)
 871                 sg_req = &chan->desc->sg_req[chan->desc->num_sgs - 1];
 872         else
 873                 sg_req = &chan->desc->sg_req[chan->next_sg - 1];
 874
 875         ndtr = sg_req->chan_reg.dma_sndtr;
 876         offset = (ndtr - chan_reg.dma_sndtr);
 877         offset <<= FIELD_GET(STM32_DMA_SCR_PSIZE_MASK, chan_reg.dma_scr);
 878         spar = sg_req->chan_reg.dma_spar;
 879         sm0ar = sg_req->chan_reg.dma_sm0ar;
 880         sm1ar = sg_req->chan_reg.dma_sm1ar;
 881
 882         /*
 883          * The peripheral and/or memory addresses have to be updated in order to adjust the
 884          * address pointers. Need to check increment.
 885          */
 886         if (chan_reg.dma_scr & STM32_DMA_SCR_PINC)
 887                 stm32_dma_write(dmadev, STM32_DMA_SPAR(id), spar + offset);
 888         else
 889                 stm32_dma_write(dmadev, STM32_DMA_SPAR(id), spar);
 890
 891         if (!(chan_reg.dma_scr & STM32_DMA_SCR_MINC))
 892                 offset = 0;
 893
 894         /*
 895          * In case of DBM, the current target could be SM1AR.
 896          * Need to temporarily deactivate CIRC/DBM to finish the current transfer, so
 897          * SM0AR becomes the current target and must be updated with SM1AR + offset if CT=1.
 898          */
 899         if ((chan_reg.dma_scr & STM32_DMA_SCR_DBM) && (chan_reg.dma_scr & STM32_DMA_SCR_CT))
 900                 stm32_dma_write(dmadev, STM32_DMA_SM1AR(id), sm1ar + offset);
 901         else
 902                 stm32_dma_write(dmadev, STM32_DMA_SM0AR(id), sm0ar + offset);
 903
 904         /* NDTR must be restored otherwise internal HW counter won't be correctly reset */
 905         stm32_dma_write(dmadev, STM32_DMA_SNDTR(id), chan_reg.dma_sndtr);
 906
 907         /*
 908          * Need to temporarily deactivate CIRC/DBM until next Transfer Complete interrupt,
 909          * otherwise NDTR autoreload value will be wrong (lower than the initial period length)
 910          */
 911         if (chan_reg.dma_scr & (STM32_DMA_SCR_CIRC | STM32_DMA_SCR_DBM))
 912                 chan_reg.dma_scr &= ~(STM32_DMA_SCR_CIRC | STM32_DMA_SCR_DBM);
 913
 914         if (chan_reg.dma_scr & STM32_DMA_SCR_DBM)
 915                 stm32_dma_configure_next_sg(chan);
 916
 917         stm32_dma_dump_reg(chan);
 918
 919         /* The stream may then be re-enabled to restart transfer from the point it was stopped */
 920         chan->status = DMA_IN_PROGRESS;
 921         chan_reg.dma_scr |= STM32_DMA_SCR_EN;
 922         stm32_dma_write(dmadev, STM32_DMA_SCR(id), chan_reg.dma_scr);
 923
 924         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 925
 926         dev_dbg(chan2dev(chan), "vchan %pK: resumed\n", &chan->vchan);
 927
 928         return 0;
 929 }
 930
 931 static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
 932                                     enum dma_transfer_direction direction,
 933                                     enum dma_slave_buswidth *buswidth,
 934                                     u32 buf_len, dma_addr_t buf_addr)
 935 {
 936         enum dma_slave_buswidth src_addr_width, dst_addr_width;
 937         int src_bus_width, dst_bus_width;
 938         int src_burst_size, dst_burst_size;
 939         u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst;
 940         u32 dma_scr, fifoth;
 941
 942         src_addr_width = chan->dma_sconfig.src_addr_width;
 943         dst_addr_width = chan->dma_sconfig.dst_addr_width;
 944         src_maxburst = chan->dma_sconfig.src_maxburst;
 945         dst_maxburst = chan->dma_sconfig.dst_maxburst;
 946         fifoth = chan->threshold;
 947
 948         switch (direction) {
 949         case DMA_MEM_TO_DEV:
 950                 /* Set device data size */
 951                 dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
 952                 if (dst_bus_width < 0)
 953                         return dst_bus_width;
 954
 955                 /* Set device burst size */
 956                 dst_best_burst = stm32_dma_get_best_burst(buf_len,
 957                                                           dst_maxburst,
 958                                                           fifoth,
 959                                                           dst_addr_width);
 960
 961                 dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
 962                 if (dst_burst_size < 0)
 963                         return dst_burst_size;
 964
 965                 /* Set memory data size */
 966                 src_addr_width = stm32_dma_get_max_width(buf_len, buf_addr,
 967                                                          fifoth);
 968                 chan->mem_width = src_addr_width;
 969                 src_bus_width = stm32_dma_get_width(chan, src_addr_width);
 970                 if (src_bus_width < 0)
 971                         return src_bus_width;
 972
 973                 /*
 974                  * Set memory burst size - burst not possible if address is not aligned on
 975                  * the address boundary equal to the size of the transfer
 976                  */
 977                 if (buf_addr & (buf_len - 1))
 978                         src_maxburst = 1;
 979                 else
 980                         src_maxburst = STM32_DMA_MAX_BURST;
 981                 src_best_burst = stm32_dma_get_best_burst(buf_len,
 982                                                           src_maxburst,
 983                                                           fifoth,
 984                                                           src_addr_width);
 985                 src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
 986                 if (src_burst_size < 0)
 987                         return src_burst_size;
 988
 989                 dma_scr = FIELD_PREP(STM32_DMA_SCR_DIR_MASK, STM32_DMA_MEM_TO_DEV) |
 990                         FIELD_PREP(STM32_DMA_SCR_PSIZE_MASK, dst_bus_width) |
 991                         FIELD_PREP(STM32_DMA_SCR_MSIZE_MASK, src_bus_width) |
 992                         FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, dst_burst_size) |
 993                         FIELD_PREP(STM32_DMA_SCR_MBURST_MASK, src_burst_size);
 994
 995                 /* Set FIFO threshold */
 996                 chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
 997                 if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE)
 998                         chan->chan_reg.dma_sfcr |= FIELD_PREP(STM32_DMA_SFCR_FTH_MASK, fifoth);
 999
1000                 /* Set peripheral address */
1001                 chan->chan_reg.dma_spar = chan->dma_sconfig.dst_addr;
1002                 *buswidth = dst_addr_width;
1003                 break;
1004
1005         case DMA_DEV_TO_MEM:
1006                 /* Set device data size */
1007                 src_bus_width = stm32_dma_get_width(chan, src_addr_width);
1008                 if (src_bus_width < 0)
1009                         return src_bus_width;
1010
1011                 /* Set device burst size */
1012                 src_best_burst = stm32_dma_get_best_burst(buf_len,
1013                                                           src_maxburst,
1014                                                           fifoth,
1015                                                           src_addr_width);
1016                 chan->mem_burst = src_best_burst;
1017                 src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
1018                 if (src_burst_size < 0)
1019                         return src_burst_size;
1020
1021                 /* Set memory data size */
1022                 dst_addr_width = stm32_dma_get_max_width(buf_len, buf_addr,
1023                                                          fifoth);
1024                 chan->mem_width = dst_addr_width;
1025                 dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
1026                 if (dst_bus_width < 0)
1027                         return dst_bus_width;
1028
1029                 /*
1030                  * Set memory burst size - burst not possible if address is not aligned on
1031                  * the address boundary equal to the size of the transfer
1032                  */
1033                 if (buf_addr & (buf_len - 1))
1034                         dst_maxburst = 1;
1035                 else
1036                         dst_maxburst = STM32_DMA_MAX_BURST;
1037                 dst_best_burst = stm32_dma_get_best_burst(buf_len,
1038                                                           dst_maxburst,
1039                                                           fifoth,
1040                                                           dst_addr_width);
1041                 chan->mem_burst = dst_best_burst;
1042                 dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
1043                 if (dst_burst_size < 0)
1044                         return dst_burst_size;
1045
1046                 dma_scr = FIELD_PREP(STM32_DMA_SCR_DIR_MASK, STM32_DMA_DEV_TO_MEM) |
1047                         FIELD_PREP(STM32_DMA_SCR_PSIZE_MASK, src_bus_width) |
1048                         FIELD_PREP(STM32_DMA_SCR_MSIZE_MASK, dst_bus_width) |
1049                         FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, src_burst_size) |
1050                         FIELD_PREP(STM32_DMA_SCR_MBURST_MASK, dst_burst_size);
1051
1052                 /* Set FIFO threshold */
1053                 chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
1054                 if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE)
1055                         chan->chan_reg.dma_sfcr |= FIELD_PREP(STM32_DMA_SFCR_FTH_MASK, fifoth);
1056
1057                 /* Set peripheral address */
1058                 chan->chan_reg.dma_spar = chan->dma_sconfig.src_addr;
1059                 *buswidth = chan->dma_sconfig.src_addr_width;
1060                 break;
1061
1062         default:
1063                 dev_err(chan2dev(chan), "Dma direction is not supported\n");
1064                 return -EINVAL;
1065         }
1066
1067         stm32_dma_set_fifo_config(chan, src_best_burst, dst_best_burst);
1068
1069         /* Set DMA control register */
1070         chan->chan_reg.dma_scr &= ~(STM32_DMA_SCR_DIR_MASK |
1071                         STM32_DMA_SCR_PSIZE_MASK | STM32_DMA_SCR_MSIZE_MASK |
1072                         STM32_DMA_SCR_PBURST_MASK | STM32_DMA_SCR_MBURST_MASK);
1073         chan->chan_reg.dma_scr |= dma_scr;
1074
1075         return 0;
1076 }
1077
1078 static void stm32_dma_clear_reg(struct stm32_dma_chan_reg *regs)
1079 {
1080         memset(regs, 0, sizeof(struct stm32_dma_chan_reg));
1081 }
1082
1083 static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg(
1084         struct dma_chan *c, struct scatterlist *sgl,
1085         u32 sg_len, enum dma_transfer_direction direction,
1086         unsigned long flags, void *context)
1087 {
1088         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1089         struct stm32_dma_desc *desc;
1090         struct scatterlist *sg;
1091         enum dma_slave_buswidth buswidth;
1092         u32 nb_data_items;
1093         int i, ret;
1094
1095         if (!chan->config_init) {
1096                 dev_err(chan2dev(chan), "dma channel is not configured\n");
1097                 return NULL;
1098         }
1099
1100         if (sg_len < 1) {
1101                 dev_err(chan2dev(chan), "Invalid segment length %d\n", sg_len);
1102                 return NULL;
1103         }
1104
1105         desc = kzalloc(struct_size(desc, sg_req, sg_len), GFP_NOWAIT);
1106         if (!desc)
1107                 return NULL;
1108
1109         /* Set peripheral flow controller */
1110         if (chan->dma_sconfig.device_fc)
1111                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_PFCTRL;
1112         else
1113                 chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
1114
1115         /* Activate Double Buffer Mode if DMA triggers STM32 MDMA and more than 1 sg */
1116         if (chan->trig_mdma && sg_len > 1)
1117                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_DBM;
1118
1119         for_each_sg(sgl, sg, sg_len, i) {
1120                 ret = stm32_dma_set_xfer_param(chan, direction, &buswidth,
1121                                                sg_dma_len(sg),
1122                                                sg_dma_address(sg));
1123                 if (ret < 0)
1124                         goto err;
1125
1126                 desc->sg_req[i].len = sg_dma_len(sg);
1127
1128                 nb_data_items = desc->sg_req[i].len / buswidth;
1129                 if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) {
1130                         dev_err(chan2dev(chan), "nb items not supported\n");
1131                         goto err;
1132                 }
1133
1134                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
1135                 desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
1136                 desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
1137                 desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
1138                 desc->sg_req[i].chan_reg.dma_sm0ar = sg_dma_address(sg);
1139                 desc->sg_req[i].chan_reg.dma_sm1ar = sg_dma_address(sg);
1140                 if (chan->trig_mdma)
1141                         desc->sg_req[i].chan_reg.dma_sm1ar += sg_dma_len(sg);
1142                 desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
1143         }
1144
1145         desc->num_sgs = sg_len;
1146         desc->cyclic = false;
1147
1148         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
1149
1150 err:
1151         kfree(desc);
1152         return NULL;
1153 }
1154
1155 static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic(
1156         struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
1157         size_t period_len, enum dma_transfer_direction direction,
1158         unsigned long flags)
1159 {
1160         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1161         struct stm32_dma_desc *desc;
1162         enum dma_slave_buswidth buswidth;
1163         u32 num_periods, nb_data_items;
1164         int i, ret;
1165
1166         if (!buf_len || !period_len) {
1167                 dev_err(chan2dev(chan), "Invalid buffer/period len\n");
1168                 return NULL;
1169         }
1170
1171         if (!chan->config_init) {
1172                 dev_err(chan2dev(chan), "dma channel is not configured\n");
1173                 return NULL;
1174         }
1175
1176         if (buf_len % period_len) {
1177                 dev_err(chan2dev(chan), "buf_len not multiple of period_len\n");
1178                 return NULL;
1179         }
1180
1181         /*
1182          * We allow to take more number of requests till DMA is
1183          * not started. The driver will loop over all requests.
1184          * Once DMA is started then new requests can be queued only after
1185          * terminating the DMA.
1186          */
1187         if (chan->busy) {
1188                 dev_err(chan2dev(chan), "Request not allowed when dma busy\n");
1189                 return NULL;
1190         }
1191
1192         ret = stm32_dma_set_xfer_param(chan, direction, &buswidth, period_len,
1193                                        buf_addr);
1194         if (ret < 0)
1195                 return NULL;
1196
1197         nb_data_items = period_len / buswidth;
1198         if (nb_data_items > STM32_DMA_ALIGNED_MAX_DATA_ITEMS) {
1199                 dev_err(chan2dev(chan), "number of items not supported\n");
1200                 return NULL;
1201         }
1202
1203         /*  Enable Circular mode or double buffer mode */
1204         if (buf_len == period_len) {
1205                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_CIRC;
1206         } else {
1207                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_DBM;
1208                 chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_CT;
1209         }
1210
1211         /* Clear periph ctrl if client set it */
1212         chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
1213
1214         num_periods = buf_len / period_len;
1215
1216         desc = kzalloc(struct_size(desc, sg_req, num_periods), GFP_NOWAIT);
1217         if (!desc)
1218                 return NULL;
1219
1220         for (i = 0; i < num_periods; i++) {
1221                 desc->sg_req[i].len = period_len;
1222
1223                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
1224                 desc->sg_req[i].chan_reg.dma_scr = chan->chan_reg.dma_scr;
1225                 desc->sg_req[i].chan_reg.dma_sfcr = chan->chan_reg.dma_sfcr;
1226                 desc->sg_req[i].chan_reg.dma_spar = chan->chan_reg.dma_spar;
1227                 desc->sg_req[i].chan_reg.dma_sm0ar = buf_addr;
1228                 desc->sg_req[i].chan_reg.dma_sm1ar = buf_addr;
1229                 if (chan->trig_mdma)
1230                         desc->sg_req[i].chan_reg.dma_sm1ar += period_len;
1231                 desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items;
1232                 if (!chan->trig_mdma)
1233                         buf_addr += period_len;
1234         }
1235
1236         desc->num_sgs = num_periods;
1237         desc->cyclic = true;
1238
1239         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
1240 }
1241
1242 static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy(
1243         struct dma_chan *c, dma_addr_t dest,
1244         dma_addr_t src, size_t len, unsigned long flags)
1245 {
1246         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1247         enum dma_slave_buswidth max_width;
1248         struct stm32_dma_desc *desc;
1249         size_t xfer_count, offset;
1250         u32 num_sgs, best_burst, dma_burst, threshold;
1251         int i;
1252
1253         num_sgs = DIV_ROUND_UP(len, STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
1254         desc = kzalloc(struct_size(desc, sg_req, num_sgs), GFP_NOWAIT);
1255         if (!desc)
1256                 return NULL;
1257
1258         threshold = chan->threshold;
1259
1260         for (offset = 0, i = 0; offset < len; offset += xfer_count, i++) {
1261                 xfer_count = min_t(size_t, len - offset,
1262                                    STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
1263
1264                 /* Compute best burst size */
1265                 max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
1266                 best_burst = stm32_dma_get_best_burst(len, STM32_DMA_MAX_BURST,
1267                                                       threshold, max_width);
1268                 dma_burst = stm32_dma_get_burst(chan, best_burst);
1269
1270                 stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
1271                 desc->sg_req[i].chan_reg.dma_scr =
1272                         FIELD_PREP(STM32_DMA_SCR_DIR_MASK, STM32_DMA_MEM_TO_MEM) |
1273                         FIELD_PREP(STM32_DMA_SCR_PBURST_MASK, dma_burst) |
1274                         FIELD_PREP(STM32_DMA_SCR_MBURST_MASK, dma_burst) |
1275                         STM32_DMA_SCR_MINC |
1276                         STM32_DMA_SCR_PINC |
1277                         STM32_DMA_SCR_TCIE |
1278                         STM32_DMA_SCR_TEIE;
1279                 desc->sg_req[i].chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
1280                 desc->sg_req[i].chan_reg.dma_sfcr |= FIELD_PREP(STM32_DMA_SFCR_FTH_MASK, threshold);
1281                 desc->sg_req[i].chan_reg.dma_spar = src + offset;
1282                 desc->sg_req[i].chan_reg.dma_sm0ar = dest + offset;
1283                 desc->sg_req[i].chan_reg.dma_sndtr = xfer_count;
1284                 desc->sg_req[i].len = xfer_count;
1285         }
1286
1287         desc->num_sgs = num_sgs;
1288         desc->cyclic = false;
1289
1290         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
1291 }
1292
1293 static u32 stm32_dma_get_remaining_bytes(struct stm32_dma_chan *chan)
1294 {
1295         u32 dma_scr, width, ndtr;
1296         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1297
1298         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
1299         width = FIELD_GET(STM32_DMA_SCR_PSIZE_MASK, dma_scr);
1300         ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
1301
1302         return ndtr << width;
1303 }
1304
1305 /**
1306  * stm32_dma_is_current_sg - check that expected sg_req is currently transferred
1307  * @chan: dma channel
1308  *
1309  * This function called when IRQ are disable, checks that the hardware has not
1310  * switched on the next transfer in double buffer mode. The test is done by
1311  * comparing the next_sg memory address with the hardware related register
1312  * (based on CT bit value).
1313  *
1314  * Returns true if expected current transfer is still running or double
1315  * buffer mode is not activated.
1316  */
1317 static bool stm32_dma_is_current_sg(struct stm32_dma_chan *chan)
1318 {
1319         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1320         struct stm32_dma_sg_req *sg_req;
1321         u32 dma_scr, dma_smar, id, period_len;
1322
1323         id = chan->id;
1324         dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
1325
1326         /* In cyclic CIRC but not DBM, CT is not used */
1327         if (!(dma_scr & STM32_DMA_SCR_DBM))
1328                 return true;
1329
1330         sg_req = &chan->desc->sg_req[chan->next_sg];
1331         period_len = sg_req->len;
1332
1333         /* DBM - take care of a previous pause/resume not yet post reconfigured */
1334         if (dma_scr & STM32_DMA_SCR_CT) {
1335                 dma_smar = stm32_dma_read(dmadev, STM32_DMA_SM0AR(id));
1336                 /*
1337                  * If transfer has been pause/resumed,
1338                  * SM0AR is in the range of [SM0AR:SM0AR+period_len]
1339                  */
1340                 return (dma_smar >= sg_req->chan_reg.dma_sm0ar &&
1341                         dma_smar < sg_req->chan_reg.dma_sm0ar + period_len);
1342         }
1343
1344         dma_smar = stm32_dma_read(dmadev, STM32_DMA_SM1AR(id));
1345         /*
1346          * If transfer has been pause/resumed,
1347          * SM1AR is in the range of [SM1AR:SM1AR+period_len]
1348          */
1349         return (dma_smar >= sg_req->chan_reg.dma_sm1ar &&
1350                 dma_smar < sg_req->chan_reg.dma_sm1ar + period_len);
1351 }
1352
1353 static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan,
1354                                      struct stm32_dma_desc *desc,
1355                                      u32 next_sg)
1356 {
1357         u32 modulo, burst_size;
1358         u32 residue;
1359         u32 n_sg = next_sg;
1360         struct stm32_dma_sg_req *sg_req = &chan->desc->sg_req[chan->next_sg];
1361         int i;
1362
1363         /*
1364          * Calculate the residue means compute the descriptors
1365          * information:
1366          * - the sg_req currently transferred
1367          * - the Hardware remaining position in this sg (NDTR bits field).
1368          *
1369          * A race condition may occur if DMA is running in cyclic or double
1370          * buffer mode, since the DMA register are automatically reloaded at end
1371          * of period transfer. The hardware may have switched to the next
1372          * transfer (CT bit updated) just before the position (SxNDTR reg) is
1373          * read.
1374          * In this case the SxNDTR reg could (or not) correspond to the new
1375          * transfer position, and not the expected one.
1376          * The strategy implemented in the stm32 driver is to:
1377          *  - read the SxNDTR register
1378          *  - crosscheck that hardware is still in current transfer.
1379          * In case of switch, we can assume that the DMA is at the beginning of
1380          * the next transfer. So we approximate the residue in consequence, by
1381          * pointing on the beginning of next transfer.
1382          *
1383          * This race condition doesn't apply for none cyclic mode, as double
1384          * buffer is not used. In such situation registers are updated by the
1385          * software.
1386          */
1387
1388         residue = stm32_dma_get_remaining_bytes(chan);
1389
1390         if (chan->desc->cyclic && !stm32_dma_is_current_sg(chan)) {
1391                 n_sg++;
1392                 if (n_sg == chan->desc->num_sgs)
1393                         n_sg = 0;
1394                 residue = sg_req->len;
1395         }
1396
1397         /*
1398          * In cyclic mode, for the last period, residue = remaining bytes
1399          * from NDTR,
1400          * else for all other periods in cyclic mode, and in sg mode,
1401          * residue = remaining bytes from NDTR + remaining
1402          * periods/sg to be transferred
1403          */
1404         if (!chan->desc->cyclic || n_sg != 0)
1405                 for (i = n_sg; i < desc->num_sgs; i++)
1406                         residue += desc->sg_req[i].len;
1407
1408         if (!chan->mem_burst)
1409                 return residue;
1410
1411         burst_size = chan->mem_burst * chan->mem_width;
1412         modulo = residue % burst_size;
1413         if (modulo)
1414                 residue = residue - modulo + burst_size;
1415
1416         return residue;
1417 }
1418
1419 static enum dma_status stm32_dma_tx_status(struct dma_chan *c,
1420                                            dma_cookie_t cookie,
1421                                            struct dma_tx_state *state)
1422 {
1423         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1424         struct virt_dma_desc *vdesc;
1425         enum dma_status status;
1426         unsigned long flags;
1427         u32 residue = 0;
1428
1429         status = dma_cookie_status(c, cookie, state);
1430         if (status == DMA_COMPLETE)
1431                 return status;
1432
1433         status = chan->status;
1434
1435         if (!state)
1436                 return status;
1437
1438         spin_lock_irqsave(&chan->vchan.lock, flags);
1439         vdesc = vchan_find_desc(&chan->vchan, cookie);
1440         if (chan->desc && cookie == chan->desc->vdesc.tx.cookie)
1441                 residue = stm32_dma_desc_residue(chan, chan->desc,
1442                                                  chan->next_sg);
1443         else if (vdesc)
1444                 residue = stm32_dma_desc_residue(chan,
1445                                                  to_stm32_dma_desc(vdesc), 0);
1446         dma_set_residue(state, residue);
1447
1448         spin_unlock_irqrestore(&chan->vchan.lock, flags);
1449
1450         return status;
1451 }
1452
1453 static int stm32_dma_alloc_chan_resources(struct dma_chan *c)
1454 {
1455         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1456         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1457         int ret;
1458
1459         chan->config_init = false;
1460
1461         ret = pm_runtime_resume_and_get(dmadev->ddev.dev);
1462         if (ret < 0)
1463                 return ret;
1464
1465         ret = stm32_dma_disable_chan(chan);
1466         if (ret < 0)
1467                 pm_runtime_put(dmadev->ddev.dev);
1468
1469         return ret;
1470 }
1471
1472 static void stm32_dma_free_chan_resources(struct dma_chan *c)
1473 {
1474         struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
1475         struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
1476         unsigned long flags;
1477
1478         dev_dbg(chan2dev(chan), "Freeing channel %d\n", chan->id);
1479
1480         if (chan->busy) {
1481                 spin_lock_irqsave(&chan->vchan.lock, flags);
1482                 stm32_dma_stop(chan);
1483                 chan->desc = NULL;
1484                 spin_unlock_irqrestore(&chan->vchan.lock, flags);
1485         }
1486
1487         pm_runtime_put(dmadev->ddev.dev);
1488
1489         vchan_free_chan_resources(to_virt_chan(c));
1490         stm32_dma_clear_reg(&chan->chan_reg);
1491         chan->threshold = 0;
1492 }
1493
1494 static void stm32_dma_desc_free(struct virt_dma_desc *vdesc)
1495 {
1496         kfree(container_of(vdesc, struct stm32_dma_desc, vdesc));
1497 }
1498
1499 static void stm32_dma_set_config(struct stm32_dma_chan *chan,
1500                                  struct stm32_dma_cfg *cfg)
1501 {
1502         stm32_dma_clear_reg(&chan->chan_reg);
1503
1504         chan->chan_reg.dma_scr = cfg->stream_config & STM32_DMA_SCR_CFG_MASK;
1505         chan->chan_reg.dma_scr |= FIELD_PREP(STM32_DMA_SCR_REQ_MASK, cfg->request_line);
1506
1507         /* Enable Interrupts  */
1508         chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE;
1509
1510         chan->threshold = FIELD_GET(STM32_DMA_THRESHOLD_FTR_MASK, cfg->features);
1511         if (FIELD_GET(STM32_DMA_DIRECT_MODE_MASK, cfg->features))
1512                 chan->threshold = STM32_DMA_FIFO_THRESHOLD_NONE;
1513         if (FIELD_GET(STM32_DMA_ALT_ACK_MODE_MASK, cfg->features))
1514                 chan->chan_reg.dma_scr |= STM32_DMA_SCR_TRBUFF;
1515         chan->mdma_config.stream_id = FIELD_GET(STM32_DMA_MDMA_STREAM_ID_MASK, cfg->features);
1516 }
1517
1518 static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec,
1519                                            struct of_dma *ofdma)
1520 {
1521         struct stm32_dma_device *dmadev = ofdma->of_dma_data;
1522         struct device *dev = dmadev->ddev.dev;
1523         struct stm32_dma_cfg cfg;
1524         struct stm32_dma_chan *chan;
1525         struct dma_chan *c;
1526
1527         if (dma_spec->args_count < 4) {
1528                 dev_err(dev, "Bad number of cells\n");
1529                 return NULL;
1530         }
1531
1532         cfg.channel_id = dma_spec->args[0];
1533         cfg.request_line = dma_spec->args[1];
1534         cfg.stream_config = dma_spec->args[2];
1535         cfg.features = dma_spec->args[3];
1536
1537         if (cfg.channel_id >= STM32_DMA_MAX_CHANNELS ||
1538             cfg.request_line >= STM32_DMA_MAX_REQUEST_ID) {
1539                 dev_err(dev, "Bad channel and/or request id\n");
1540                 return NULL;
1541         }
1542
1543         chan = &dmadev->chan[cfg.channel_id];
1544
1545         c = dma_get_slave_channel(&chan->vchan.chan);
1546         if (!c) {
1547                 dev_err(dev, "No more channels available\n");
1548                 return NULL;
1549         }
1550
1551         stm32_dma_set_config(chan, &cfg);
1552
1553         return c;
1554 }
1555
1556 static const struct of_device_id stm32_dma_of_match[] = {
1557         { .compatible = "st,stm32-dma", },
1558         { /* sentinel */ },
1559 };
1560 MODULE_DEVICE_TABLE(of, stm32_dma_of_match);
1561
1562 static int stm32_dma_probe(struct platform_device *pdev)
1563 {
1564         struct stm32_dma_chan *chan;
1565         struct stm32_dma_device *dmadev;
1566         struct dma_device *dd;
1567         const struct of_device_id *match;
1568         struct resource *res;
1569         struct reset_control *rst;
1570         int i, ret;
1571
1572         match = of_match_device(stm32_dma_of_match, &pdev->dev);
1573         if (!match) {
1574                 dev_err(&pdev->dev, "Error: No device match found\n");
1575                 return -ENODEV;
1576         }
1577
1578         dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
1579         if (!dmadev)
1580                 return -ENOMEM;
1581
1582         dd = &dmadev->ddev;
1583
1584         dmadev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
1585         if (IS_ERR(dmadev->base))
1586                 return PTR_ERR(dmadev->base);
1587
1588         dmadev->clk = devm_clk_get(&pdev->dev, NULL);
1589         if (IS_ERR(dmadev->clk))
1590                 return dev_err_probe(&pdev->dev, PTR_ERR(dmadev->clk), "Can't get clock\n");
1591
1592         ret = clk_prepare_enable(dmadev->clk);
1593         if (ret < 0) {
1594                 dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
1595                 return ret;
1596         }
1597
1598         dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node,
1599                                                 "st,mem2mem");
1600
1601         rst = devm_reset_control_get(&pdev->dev, NULL);
1602         if (IS_ERR(rst)) {
1603                 ret = PTR_ERR(rst);
1604                 if (ret == -EPROBE_DEFER)
1605                         goto clk_free;
1606         } else {
1607                 reset_control_assert(rst);
1608                 udelay(2);
1609                 reset_control_deassert(rst);
1610         }
1611
1612         dma_set_max_seg_size(&pdev->dev, STM32_DMA_ALIGNED_MAX_DATA_ITEMS);
1613
1614         dma_cap_set(DMA_SLAVE, dd->cap_mask);
1615         dma_cap_set(DMA_PRIVATE, dd->cap_mask);
1616         dma_cap_set(DMA_CYCLIC, dd->cap_mask);
1617         dd->device_alloc_chan_resources = stm32_dma_alloc_chan_resources;
1618         dd->device_free_chan_resources = stm32_dma_free_chan_resources;
1619         dd->device_tx_status = stm32_dma_tx_status;
1620         dd->device_issue_pending = stm32_dma_issue_pending;
1621         dd->device_prep_slave_sg = stm32_dma_prep_slave_sg;
1622         dd->device_prep_dma_cyclic = stm32_dma_prep_dma_cyclic;
1623         dd->device_config = stm32_dma_slave_config;
1624         dd->device_pause = stm32_dma_pause;
1625         dd->device_resume = stm32_dma_resume;
1626         dd->device_terminate_all = stm32_dma_terminate_all;
1627         dd->device_synchronize = stm32_dma_synchronize;
1628         dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1629                 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1630                 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1631         dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1632                 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1633                 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1634         dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1635         dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
1636         dd->copy_align = DMAENGINE_ALIGN_32_BYTES;
1637         dd->max_burst = STM32_DMA_MAX_BURST;
1638         dd->max_sg_burst = STM32_DMA_ALIGNED_MAX_DATA_ITEMS;
1639         dd->descriptor_reuse = true;
1640         dd->dev = &pdev->dev;
1641         INIT_LIST_HEAD(&dd->channels);
1642
1643         if (dmadev->mem2mem) {
1644                 dma_cap_set(DMA_MEMCPY, dd->cap_mask);
1645                 dd->device_prep_dma_memcpy = stm32_dma_prep_dma_memcpy;
1646                 dd->directions |= BIT(DMA_MEM_TO_MEM);
1647         }
1648
1649         for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
1650                 chan = &dmadev->chan[i];
1651                 chan->id = i;
1652                 chan->vchan.desc_free = stm32_dma_desc_free;
1653                 vchan_init(&chan->vchan, dd);
1654
1655                 chan->mdma_config.ifcr = res->start;
1656                 chan->mdma_config.ifcr += STM32_DMA_IFCR(chan->id);
1657
1658                 chan->mdma_config.tcf = STM32_DMA_TCI;
1659                 chan->mdma_config.tcf <<= STM32_DMA_FLAGS_SHIFT(chan->id);
1660         }
1661
1662         ret = dma_async_device_register(dd);
1663         if (ret)
1664                 goto clk_free;
1665
1666         for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) {
1667                 chan = &dmadev->chan[i];
1668                 ret = platform_get_irq(pdev, i);
1669                 if (ret < 0)
1670                         goto err_unregister;
1671                 chan->irq = ret;
1672
1673                 ret = devm_request_irq(&pdev->dev, chan->irq,
1674                                        stm32_dma_chan_irq, 0,
1675                                        dev_name(chan2dev(chan)), chan);
1676                 if (ret) {
1677                         dev_err(&pdev->dev,
1678                                 "request_irq failed with err %d channel %d\n",
1679                                 ret, i);
1680                         goto err_unregister;
1681                 }
1682         }
1683
1684         ret = of_dma_controller_register(pdev->dev.of_node,
1685                                          stm32_dma_of_xlate, dmadev);
1686         if (ret < 0) {
1687                 dev_err(&pdev->dev,
1688                         "STM32 DMA DMA OF registration failed %d\n", ret);
1689                 goto err_unregister;
1690         }
1691
1692         platform_set_drvdata(pdev, dmadev);
1693
1694         pm_runtime_set_active(&pdev->dev);
1695         pm_runtime_enable(&pdev->dev);
1696         pm_runtime_get_noresume(&pdev->dev);
1697         pm_runtime_put(&pdev->dev);
1698
1699         dev_info(&pdev->dev, "STM32 DMA driver registered\n");
1700
1701         return 0;
1702
1703 err_unregister:
1704         dma_async_device_unregister(dd);
1705 clk_free:
1706         clk_disable_unprepare(dmadev->clk);
1707
1708         return ret;
1709 }
1710
1711 #ifdef CONFIG_PM
1712 static int stm32_dma_runtime_suspend(struct device *dev)
1713 {
1714         struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
1715
1716         clk_disable_unprepare(dmadev->clk);
1717
1718         return 0;
1719 }
1720
1721 static int stm32_dma_runtime_resume(struct device *dev)
1722 {
1723         struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
1724         int ret;
1725
1726         ret = clk_prepare_enable(dmadev->clk);
1727         if (ret) {
1728                 dev_err(dev, "failed to prepare_enable clock\n");
1729                 return ret;
1730         }
1731
1732         return 0;
1733 }
1734 #endif
1735
1736 #ifdef CONFIG_PM_SLEEP
1737 static int stm32_dma_pm_suspend(struct device *dev)
1738 {
1739         struct stm32_dma_device *dmadev = dev_get_drvdata(dev);
1740         int id, ret, scr;
1741
1742         ret = pm_runtime_resume_and_get(dev);
1743         if (ret < 0)
1744                 return ret;
1745
1746         for (id = 0; id < STM32_DMA_MAX_CHANNELS; id++) {
1747                 scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id));
1748                 if (scr & STM32_DMA_SCR_EN) {
1749                         dev_warn(dev, "Suspend is prevented by Chan %i\n", id);
1750                         return -EBUSY;
1751                 }
1752         }
1753
1754         pm_runtime_put_sync(dev);
1755
1756         pm_runtime_force_suspend(dev);
1757
1758         return 0;
1759 }
1760
1761 static int stm32_dma_pm_resume(struct device *dev)
1762 {
1763         return pm_runtime_force_resume(dev);
1764 }
1765 #endif
1766
1767 static const struct dev_pm_ops stm32_dma_pm_ops = {
1768         SET_SYSTEM_SLEEP_PM_OPS(stm32_dma_pm_suspend, stm32_dma_pm_resume)
1769         SET_RUNTIME_PM_OPS(stm32_dma_runtime_suspend,
1770                            stm32_dma_runtime_resume, NULL)
1771 };
1772
1773 static struct platform_driver stm32_dma_driver = {
1774         .driver = {
1775                 .name = "stm32-dma",
1776                 .of_match_table = stm32_dma_of_match,
1777                 .pm = &stm32_dma_pm_ops,
1778         },
1779         .probe = stm32_dma_probe,
1780 };
1781
1782 static int __init stm32_dma_init(void)
1783 {
1784         return platform_driver_register(&stm32_dma_driver);
1785 }
1786 subsys_initcall(stm32_dma_init);